This invention relates to a resectoscope which is inserted into a bladder through the urethra and has an electrode projected on the tip side through which a high frequency electric current can be passed while an affected part is being sighted so that the affected part may be resected.
The above mentioned resectoscope comprises a scope (optical sighting tube), an electrode, a resectoscope sheath through which the scope and electrode are inserted, a grip provided to project below the rear part of this resectoscope sheath and a movable member fixing the above mentioned electrode at the rear end and provided with a finger hanger so that, when fingers of one hand are inserted in the grip of the above mentioned resectoscope sheath and the finger hanger of the movable member to grip them so as to slide and reciprocate the movable member forward and rearward, that is, by making the fingers approach each other and separate from each other, the electrode on the tip side will be advanced and retreated from an opening at the tip of the resectoscope sheath to make a resection or the like.
However, in the conventional resectoscope, the resecting electrode is electrically connected at the rear end with the electrode cord by the following formation.
That is to say, while an electrode inserting hole is made from the tip surface of the above mentioned movable member to the rear middle, on the respective side surfaces of the movable member in the positions holding this inserting hole, a mouthpiece inserting hole having a plug inserting hole in which the plug at the tip of the electrode cord is inserted and a separate pressing member inserting hole are opened so as to face the above mentioned electrode inserting hole. The electrode inserted in this electrode inserting hole is pressed at the rear end on a mouthpiece inserted through the above mentioned mouthpiece inserting hole in the opposite position on the tip surface of a pressing member formed to be comparatively small and inserted through the pressing member inserting hole so that the electrode may be pressed at the rear end on the mouthpiece. The high frequency current fed from the current source may be passed to the electrode through the electrode cord, the plug at the tip of the electrode cord and the mouthpiece having the inserting hole in which this plug is inserted.
In such conventional structure of connecting the electrode with the mouthpiece, the electrode is pressed at the rear end into contact with the mouthpiece with the pressing force at the tip of a small diameter pressing member. Therefore, there have been problems that, in order that the electrode may be well connected with the mouthpiece, not only the pressing member and the mouthpiece with the electrode held between them must be aligned with each other in the producing process so as to be correctly opposed to each other but also, unless they are aligned with each other with high precision, the electric contact of the electrode with the mouthpiece will fail.
Also, in this case, when the pressing force applied to the pressing member is very large or under repeated use with the lapse of time in which the pressing force applied to the pressing member is repeatedly alternately released and given, the surface of contact of the pressing member at the tip with the electrode at the rear end or the surface of contact of the electrode at the rear end with the mouthpiece will be worn or damaged. As a result, there have been problems that the electric contact will fail on the surface of contact of the electrode at the rear end with the mouthpiece, therefore no high frequency current will be fed to the electrode and the affected part will not be able to be well resected.
Further, there is suggested in U.S. Pat. No. 2,487,502 a prior art wherein the electrode and electrode cord are electrically connected with each other as described below.
In this prior art, a mouthpiece to which the electrode cord is connected is formed to be plate-shaped at the tip and a slit is provided at the tip so as to hold the electrode at the rear end in this slit. A tightening screw is arranged in the direction at right angles with the slit so as to pull a holding piece on the side beyond the slit toward the hand side, to hold the electrode at the rear end within the slit and to electrically connect the electrode to the above mentioned mouthpiece.
However, in such prior art, there have been problems that, as a telescope can be further insulatively inserted through the above mentioned mouthpiece, the telescope and electrode can be rotatably fitted and the telescope is arranged in the center, the tightening screw will be arranged toward one side end of the body, the fitting structure for fitting this tightening screw to the body will be complicated and the production cost will be high.
Further, there has been a danger that, as the above mentioned mouthpiece part is exposed, the operator will accidentally touch the mouthpiece part so as to be electrified.
There have been further problems that the moisture and dust will be deposited on the outer surface so that the insulation will not be sufficient, even if the device is insulated from direct currents, the high frequency dielectric loss will be so large that the insulation will be insufficient, when the capacity is formed, the high frequency insulation will become insufficient and, in case the current is passed, there will be a danger of being electrified and the safety will be low.